condition mean min max ZT0-3 20.919935 20.919935 20.919935 ZT4-7 21.834781999999997 21.834781999999997 21.834781999999997 ZT8-11 22.936146 22.936146 22.936146 ZT12-15 21.768814499999998 21.768814499999998 21.768814499999998 ZT16-19 19.30067 19.30067 19.30067 ZT20-23 17.3850915 17.3850915 17.3850915